From a microbiological perspective, the primary function of normal, intact human and animal skin is to control microbial populations that live on the skin surface and to prevent underlying tissue from becoming colonized and invaded by potential pathogens. Exposure of subcutaneous tissue (i.e. a wound) provides a moist, warm and nutritious environment that is conducive to microbial colonization and proliferation.
Since wound colonization is mostly polymicrobial, involving numerous microorganisms that are potentially pathogenic, any wound is at some risk of becoming infected. In the event of an infection a wound fails to heal, the patient suffers increased trauma as well as increased treatment costs. General wound management practices become more resource demanding. Over 2% of the U.S. population suffers from such chronic, non-healing wounds and it costs the U.S. health care system $20 billion a year. Wounds are an enormous problem worldwide in humans as well as in animals.
Thus, concern among health care practitioners regarding the risk of wound infection is justifiable not only in terms of increased trauma to the patient but also in view of its burden on financial resources and the increasing requirement for cost-effective management within the health care system. Most wound infections are caused by Staphylococcus aureus (20%), Staphylococcus epidermidis (14%), Enterococci spp. (12%), Escherichia coli (8%), Pseudomonas aeruginosa (8%), Enterobacter spp. (7%), Proteus spp. (3%), Klebsiella pneumoniae (3%), Streptococci (3%) and Candida albicans (3%).
Wounds often have multiple barriers to healing. Wound healing and infection is influenced by the relationship between the ability of bacteria to create a stable, prosperous community within a wound environment and the ability of the host to control the bacterial community. Since bacteria are rapidly able to form their own protective microenvironment (biofilm) following their attachment to a surface, the ability of the host to control these organisms is likely to decrease as the biofilm community matures. Within a stable biofilm community, interactions between aerobic and anaerobic bacteria are likely to increase their net pathogenic effect, enhancing their potential to cause infection and delay healing. Over the last few years, some have linked biofilm to chronic wounds. Microscopic evaluation or chronic wounds showed well organized biofilm with extracellular polymeric substance adhered around colony bacteria in at least 60% of the chronic wounds.
In recent years, there have been numerous efforts to use antibiotics and antimicrobials for the treatment of non-healing, clinically infected wounds in humans as well as in animals. These antimicrobial agents are of varying chemical compositions and can include peptides, antiseptics (U.S. Pat. No. 6,700,032), antibiotics, silver ions/compounds (US patent appl. pub. no. 2005/0035327), chitosan (US patent appl. pub. no. 2006/0210613; U.S. Pat. No. 6,998,509), nitrofurazone, bismuth thiols, and xylitol (WO 2005/058381).
There have been various attempts by others to create wound care devices such as dressings or bandages, gels and ointments comprising antimicrobial agents. For example, U.S. Pat. No. 3,930,000 discloses the use of a silver zinc allantoinate cream for killing. From a microbiological perspective, the primary function of normal, intact human and animal skin is to control microbial populations that live on the skin surface and to prevent underlying tissue from becoming colonized and invaded by potential pathogens. Exposure of subcutaneous tissue (i.e. a wound) provides a moist, warm and nutritious environment that is conducive to microbial colonization and proliferation.
Historically, it has been presumed that the properties of bacteria that cause chronic infections were similar to those of bacteria grown suspended in liquid growth media. However, research over the past 20 years has indicated that many chronic infections are the result of the biofilm mode of microbial growth. Bacteria in biofilms can be 100 to 1000 times more resistant to antibiotics/antimicrobials compared to their planktonic counterparts. Recent studies have demonstrated biofilm as a potential reason why chronic wounds do not heal (Singh and Barbul, Wound Rep Reg. 16: 1, 2008). In addition, James et al. (Wound Rep Reg. 16: 37-44, 2008) has recently demonstrated biofilms in over 60% of bacterial infections associated with chronic wounds such as diabetic foot ulcers, venous leg ulcers and pressure ulcers.
The chronic wound infections are typically persistent infections that develop slowly, seem to be rarely resolved by immune defenses, and respond transiently to antimicrobial therapy. Thus, there is an unmet clinical need for developing wound care products with both the antibiofilm and antimicrobial activity for prevention and treatment of acute as well as chronic wounds that involve biofilms. A composition with both the antibiofilm and antimicrobial activity kills biofilm bacteria that are highly resistant to antibiotics/antimicrobials and to body's immune system by inhibiting biofilm formation and/or by disrupting preformed biofilms. Furthermore, there is also a need for a non-antibiotic wound care or disinfectant composition comprising generally recognized as safe (GRAS).
In an abattoir or meat processing plant, there is a problem of contamination of meat and apparatuses (e.g. mincing machine, cutters, slicers, mixers, fillers, or the like) with food poisoning microbials. In a conventional meat processing plant, sodium hypochlorite is used as an anti-microbial during a sterilizing process of meat. Meat such as carcasses is immersed in a solution of sodium hypochlorite for a certain time. However, there is a problem of safety for a human body of reaction products of sodium hypochlorite adhering to meat.
Thus, there is a need for an anti-microbial for sterilization of meat, with a high degree of safety for humans, and long lasting anti-microbial power. Such an anti-microbial will keep meat fresher longer and decrease or prevent degradation of products.